5 Fuel-Saving Car Features & How They Work


Over and above the rise in the government's fuel levy in April 2018, a weakening exchange rate and rising oil prices have resulted in South Africans paying record prices for fuel in June 2018. Never has there been a time where we need fuel-saving technology more than we do now. But what are some of the in-car technologies that can help us save fuel, and do they really work?

We take a look at a few that might just help you spend less at the fuel pump.

The button marked with a circled capital A denotes the Stop/Start deactivation/activation button.  


This is by no means new technology, but it came about to help make cars more fuel efficient. It works by cutting the engine when you stop the car at a traffic light or intersection (or in a traffic jam!), and as soon as you take your foot off the brake the engine starts up again. It has been disputed as to whether this technology actually saves fuel, but the consensus is that the amount of fuel saved depends almost entirely upon the type of driving done with this system. If you sit in heavily congested traffic on a daily basis, stop/start will help you save fuel. If you are doing a lot of open road driving, then it is less likely that this system will be of much use to you. 

Steering wheel-activated cruise control allows you to set and restore cruise control and adjust sustained speeds at the flick of a switch. 

Cruise Control

Another technology that has been around for many years is cruise control and, in more recent years, adaptive cruise control. This system, when activated, automatically maintains a selected constant speed so that a driver does not need to make (sometimes unnecessary) accelerator inputs to maintain a vehicle's on-road momentum. Adaptive cruise control not only employs dynamic acceleration and braking to keep your car at a constant speed, but uses a radar (or camera) to maintain a safe following distance to other vehicles. It might seem as if this technology is merely convenient, but it keeps us away from the fuel pumps for longer. A constant speed is more fuel efficient and adaptive cruise control means the car won't brake or accelerate harshly (unless prompted to do so). Convenient and money-saving; we love that.

The recently unveiled Ford Fiesta ST features a 1.5-litre 3-pot engine that can operate on only 2 cylinders to improve fuel efficiency. 

Cylinder Deactivation  

Petrolheads we are always looking for more power, but with more power comes a higher fuel cost. This is where something like cylinder deactivation technology works in our favour. It simply works by shutting off a number of cylinders that are not in use. For example, if you have a V8 engine, that engine will be using 8 cylinders all of the time, even when all of them are not required to provide propulsion and, therefore, burn fuel unnecessarily. This tech will shut off 4 of those cylinders when you are at a constant speed and do not require the added power. It is estimated that this technology can improve engine efficiency by 7.5%, and, in the case of the Fiesta ST, some smaller engines feature it too, which augers well for more widespread implementation in the near future, as long as the "controlled misfires" do not impede refinement.  

Even the Lexus CT200h petrol-electric hybrid has an Eco mode, which adjusts various vehicle settings in the pursuit of optimal efficiency. 

Eco Button

These buttons are in many cars these days, but what do they actually do? For starters, they are not just helping the environment by ensuring less emissions are emitted, but they also modify certain systems to utilise less fuel. Most Eco buttons will reduce aircon control such as turning down the fan speed, throttle and transmission behavior will be altered, a stop/start system will be activated, and automatic transmission patterns will be swapped out for more relaxed driving where the transmission will move to a higher gear ratio as quickly as possible and avoids using first gear unless necessary, this places less strain on the engine therefore uses less fuel.  

Mild Hybrid

Most of us are all fully aware of what a hybrid is by now (think Toyota Prius), it's a car that operates through a combination of petrol-fed engine and an electric motor and can operate on battery power alone for short distances. Mild hybrid technology is much closer to conventional cars with combustion engines. The difference between a mild hybrid and a full hybrid is that the electric motor does not propel the vehicle on its own. It is merely there to assist the combustion engine. It saves fuel by shutting off the engine when the vehicle is stopped, braking or cruising. Depending on the system, some mild hybrids can capture mechanical energy during braking. A mild hybrid system can improve fuel efficiency by between 10 and 15%. They cost less than that of a full hybrid, but for the moment we are only really seeing them in luxury cars such as the new Volkswagen Touareg and Mercedes-Benz S-Class. We will, however, see it trickle down to more affordable cars such as the next Volkswagen Golf.

Cheat sheet

Your car might not have any of this tech to help with your fuel consumption, but don’t panic, because by slightly changing your very own driving behaviour you can reduce your car's fuel consumption. Here are 5 easy tips to delay fill-ups as long as possible:

  • Ensure your tyres are correctly inflated

  • Avoid harsh braking or accelerating

  • Lighten the load by removing all unnecessary items from your car

  • Service your car when it is required

  • Avoid roof racks or boxes

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